Yeah, you're right. I don't mean transverse in that it is a wave in water. There is no 'water' particles there to be moving up/down left/right. Interestingly,

Yeah, you're right. I don't mean transverse in that it is a wave in water. There is no 'water' particles there to be moving up/down left/right. Interestingly, Maxwell himself worked in a time when the aether model was dominant; that there had to be something for the waves to be moving in/through. His equations held up under both the aether model and special relativity which made aether unnecessary. https://en.wikipedia.org/wiki/Luminiferous_aether https://en.wikipedia.org/wiki/Luminiferous_aether